Tanning material and method of producing the same



UNITED STATES PATENT OFFlCE.

ARTHUR KOETZLE, OF NEW YORK, N. Y.-, ASSIGNOR TO ROHM & HAAS COMPANY, A

CORPORATION OF DELAWARE. I

TANNING MATERIAL AND METHOD OF PRODUCING THE SAME.

No Drawing.

To all whom it may concern Be it known that I, ARTHUR KOETZLE, a citizen of Germany, and a resident of the city, county, and State of New York, (whose ost-ofiice address is 519 West 160th street, ew York, N. Y.,) have invented certain new and useful Improvements in T annlng Materials and Methods of Producing the Same, of which the following is a specification. The general object of my invention is the production of a tanning material, by the use of which leather of superior qualities ma be obtained.

s is described in Letters Patent of the United States 1,232,620, issued to Edmund- Stiasny, July 10, 1917, tanning materials can be produced by reacting upon phenolcarboxylic acids with formaldehyde and transforming the so obtained insoluble or diflicultly soluble products into water soluble bodies by treating them with sulfonating said patent, is the sulfonation product of the known methylenedisalicylic acid, in which the methylene group is in para-position to the hydroxyl group, and the sulfonic group is in the ortho-position to the latter. 80 The use of this tanning material results in a leather of dark color and of little utility. I have discovered that by following the method which will now be described, a tanning material can Ibe'obtained which is far superior to that described in the aforesa1d patent.

As is well known, sulfo-salicylic acid, for example, formed by sulfona'ting salicylic acid, is a chemical structure in which the sulfonic group takes the para-position to the hydroxyl group, as distinguished from the ortho-positipn, as is the case in the tanning material of the aforesaid patent. Now, although it could not in any way be foreseen that this sulfo-salicylic acid would still possess the power of producin a condensation product with formaldehy e, I have discovered not only that such a condensation will take place; but also that the product thereof, which is amorphous and readily soluble in water, constitutes an excellent tanning material. My improved method consists, therefore, in condensing with formaldehyde, or bodies giving rise to formalagents. The chemical body produced from salicylic acid, in accordance wlth the afore-.

vention, and I- have no intention in refer- Specification of Letters Patent. Patented June 29, 1920. Application filed April 12, 1919. Serial No. 289,592.

dehyde, a sulfo-phenol-carboxylic acid resultmg from the treatment of a phenolcarboxylic acid with sulfuric acid.

Instead of producing a dark colored leather of little utility, as is the casewith the tanning material of the aforesaid patent, my improved tanning material, obtained as just described, produces a leather which is not only colorless, but which is also extremely strong and pliable. This I difference in the action of the two tanning materials upon leather I attribute to the difference in their chemical structure resulting from the difference between their respective methods of production.

The following is'given as an example of one of the ways in which my invention may be carried out and my improved tanning material produced, but it is to be understood that my invention "is not in any sense limited to this particular method of procedure:

Dissolve 100 parts ofsulfo-salicylic acid in 150 parts of concentrated sulfuric acid and add gradually, while stirring, at about 50 cent, 20 parts of 40% formaldehyde solution. Agitate the mixture for several hours until the odor of formalrehyde has disappeared. Then dilute with 200 parts of water and neutralize the sulfuric acid with a solution of caustic soda or sodium as exemplifying and not as limiting my inring to such compounds and proportions of excluding from the scope of my claims any equivalents which may be recognized as such by those skilled in the art.

What I claim is:

1. A tanning material comprising the condensation product of a sulfo-phenol-carboxylic acid with formaldehyde, which pro- 'duct is amorphous, soluble in water and use in tanning and the like, which consists in condensin a sulfo-phenol-carboxylic acid with formaldehyde.

4. The process of producingmaterial' for use in tanning'and the like, which consists in sulfonating a phenol-carboxylic acid and condensing the sulfonated acid with formaldehyde. a 5. The process of producing material for use in tanning and the like, which consists in condensing sulfo-salicylic acid .with formaldehyde.

6. The process of producing material for use in tanning and the like, which consists in sulfonating salicylic acid and condensing 15 the sulfonated acid with formaldehyde.

7. A tanning material comprising the product produced by sulfonating salicylic acid and condensing the sulfonated acid with formaldehyde, which product is amorphous, 20 soluble in water and produces a leather which is substantially colorless, strong and pliable.

ARTHUR KOETZLE. 

